High-voltage electrostatic generator



Feb- 25 1964 G. M. GIANNINI ETAL HIGH-VOLTAGE ELECTROSTATIC GENERATOR 5Sheets-Sheet 1 Filed Jan. l2, 1962 1N VEN TORS VOL 72765 007007' VOL7%765 Feb. 25, 1964 G'. M. GIANNINI ETAL HIGH-VOLTAGE ELEcTRosTATIcGENERATOR 5 Sheets-Sheet 5 Filed Jan. 12, 1962 m TGE SOUQCE UnitedStates Patent O Filed Jan. 12, 1962, Ser. No. 165,778 claims. (el.31o-s) This invention relates to a highvoltage electrostatic generatorand method, and makes use of a high-velocity charge-carrying stream ofliquid droplets.

An object ot the present invention is to provide a method and apparatusfor generating electrical energy at high voltage, being characterized byextremely high charge densities in the stream of droplets.

A further object is to provide a highvoltage electrostatic generatorWhich is light in weight, and which is capable of creating highvoltagesat currents much greater than are generated in prior-art apparatus.

A further object is to provide a method and apparatus for generatinghigh voltages in an ethcient manner such that the iiow of liquiddroplets may be metered precisely to achieve the desired voltage andcurrent.

Another object is to provide a method and apparatus for generating ahigh voltage without creating the caking or crusting problems inherentin dust-type generators, without requiring the enormous belt sizesnecessary for Van de Graait generators, and without the necessity formassive equipment adapted to move large volumes of gas.

An additional object is to provide an electrostatic generator the energyfor which may be supplied solely by heat, no mechanical or moving partsbeing required, so that the generator is highly suitable and desirablefor space vehicles.

Another object is to provide a voltage generator employingcharge-carrying droplets which do work against the electrostatic eld byvirtue of their own momentum, there being no necessity that ions bedrawn along by large volumes of rapidly-flowing gas.

A further object is to provide a two-phase electrostatic generatorincorporating a liquid which is in coherent liquid form in the returnportion of the cycle.

An additional object is to provide a voltage generator incorporatingmeans interposed in the stream of droplets to provide an electricalcontrol eiiect.

These and other objects and advantages of the invention will be morefully set forth in the following specification and claims, considered inconnection with the attached drawings to which they relate.

In the drawings:

FIGURE 1 is a schematic vertical central sectional View illustrating aiirst embodiment of a high-voltage electrostatic generator constructedin accordance with the present invention;

FIGURE 2 is a schematic vertical central sectional View illustrating avoltage generator constructed in accordance with a second embodiment ofthe invention; and

FIGURE 3 is a corresponding schematic section illustrating a thirdembodiment.

Referring first to the embodiment shown in FIGURE 1, the high-voltageelectrostatic generator is illustrated to comprise an elongated tube orconduit 1t) formed of insulating material and preferably maintained invertical relationship by a suitable support means, not shown. Sealinglyconnected at the upper end of conduit 1t) is a charge-collecting metaldome or sphere 11, such sphere being associated with a voltage outputschematically represented at 12. At the lower end of conduit 1t? isprovided a metal sump element 13. Such sump is suitably associated withthe conduit 16 in sealing relationship, being grounded as indicated at14.

3,122,660 Patented Feb. 25, 1964 Coaxially mounted in vertically spaced,superposed relationship in conduit 1() are a plurality ofcharge-collecting metal domes 16-21, inclusive. The domes 16-20 aretXedly connected to the interior wall of conduit 1t) by suitable means,not shown. The upper metal dome 21 is electrically connected to thecharge-collecting sphere 11 by means of metal webs 22. It is pointed outthat the coaxially-arranged domes have major diameters somewhat lessthan the inner diameter of conduit lt), so that an annular passage isformed radially-inwardly of the interior conduit wall to permitgravitational tiow of liquid to the sump 23 deiined by element 13.

An insulating tube or conduit 25 is connected to the sump 23 and is alsoconnected, through a plurality of branch conduits, to metal nozzles 26which are respectively mounted on and electrically connected to the poleportions ot' domes 16-20. The nozzles 26 are each directed upwardly sothat the droplet sprays 27 emanating therefrom will impinge against theunder surfaces ol' domes 17-21 and will not contact the interior wall ofconduit 1d. Liquid is pumped to the nozzles by a suitable pump meansindicated at 28.

It is a feature of the invention that the pumping action may also beeliected solely by heat, without rotating mechanical parts, by providinga suitable heat source, check valve, etc. Such use of heat is highlydesirable when the electrostatic generator is employed in space.

A voltage source 31 is connected through a lead 32 to the lowermost dome16 and thus to the metal nozzle 26 mounted thereon. Metal takes .33 aremounted on each of the domes 16-2ti and have their tine portionsdisposed in the paths of the droplet sprays 27. The rakes 33 and metalnozzles 26 cooperate with each other to effect charging of the dropletswhich emanate from the nozzles.

The sump 23 is tilled with a suitable insulating liquid,

such as oil or distilled water, adapted to be pumped by the pump means2S to form the droplet sprays 27. It is emphasized that the sprays 27are formed of small discrete liquid droplets, not vapor, the nozzles 2dbeing adapted to achieve this result in a manner known to the art.

It is pointed out that the liquid droplets in sprays 27 are projectedupwardly through a gas (for example, air) which has a dilierentcomposition than that of the droplets (that is to say, is not the vaporof the liquid forming the droplets), Such shooting of droplets through agas of a different nature produces important advantages, one of which isthat the mass flow of liquid may be readily controlled in a mannerachieving the desired voltage and current. t

Description of Method, Embodl'ment of FIGURE 1 The sump 23 is filledwith a suitable insulating liquid such as a light oil or distilledwater, and pump 28 is operated to` pump such liquid at very highpressure to all of the nozzles 26. The pressure may be thousands ofpounds per square inch.

Voltage source `31 is applied to deliver a high voltage to dome 16 andits associated nozzle 26 and rake 33, such voltage being (for example)10,000 volts.

The nozzle 26 on dome 16 converts the liquid into line droplets, notvapor, which droplets are eiected upwardly in a spray 27 until theyimpinge against the next dome 17. The veiocity of the droplet spray is,because of the great pressure, very high. The droplets areelectrostatically charged due to combined action of nozzle 2o and rake33. Because of such charging, the droplets spread apart due to mutualrepulsion so that the spray 27 tends to fan out as indicated.

The droplets which impinge against the under surface of dome 17 delivertheir charge to such dome, so that the voltage of dome 'i7 increases bya very substantial amount. The droplets then run down the under surfaceof dome ll7 and drip olf the lower edge thereof, after which theygravitate downwardly to the sump 23 in the form of the relatively largedrops (not droplets) indicated at 36.

The charge on dome 17 is delivered by the associated nozzle 26 and rake33 to the stream 27 of droplets emanating from the nozzle. It followsthat the dome i3 its charged to a voltage much higher than that of dome17. The drops on dome 18 combine to form large drops 36 which gravitatedownwardly to the snmp 23 as in the case of the drops from dome 17. Inlike manner, the dome 19 is charged to a much higher voltage than dome18, and domes Zt)l and 2l are charged to very much higher voltages.Thus, by the described voltage-multiplier action, the collecting spherel1 is charged to a very high value, such as one million volts.

lt is emphasized that the droplets are very tine, so that there is anenormous amount of surface area capable of carrying electrostaticcharge. It follows that the charge density of the sprays 2'7 isextremely high, so that the current generated by the apparatus may be anumber of times greater than in prior-art apparatus.

Since the sprays 2.7 are composed of droplets and are not vapor, theyare projected at high velocities and are not subject to drift.Furthermore, and very importantly, the charges move at the same velocityas the droplets instead of at a slower velocity as is the case ingas-type electrostatic generators. A further important advantage of theuse of droplets is that the droplets combine into coherent masses (suchas larger drops) which may be readily transported back to the sump bygravity or by an auxiliary pump.

The recirculation may, if desired, be effected outside the apparatusthrough a separate conduit leading to the sump 23. Such recirculation isto be contrasted with the use `of dust particles, for example, sincesuch particles cluster together and may not be recirculated in apractical or eiiicient manner. ln constructions wherein therecirculation of liquid is forced and not gravitational, there is nonecessity of maintaining the apparatus in vertical relationship.

it is emphasized that, in the present generator wherein the liquiddroplets are shot through a gas (such as air) of a different nature thanthe liquid, the mass flow of liquid may be readily controlled by varyingthe operation of pump 23 or by auxiliary valve means (not shown). Thedroplets employed in the present apparatus are relatively insensitive totemperature gradients therein.

The described generator may lbe termed a two-phase apparatus since theliquid is in the form of very ne droplets while in sprays 27, but is incoherent masses while in the drops 36 and in the sump 223 and associatedconduit 25. It is also pointed out that, in certain applications, thedroplets may be frozen (ice) which melts to the liquid phase uponreaching the adjacent domes 7-2l. The use in the claims of the termtwo-phase is, however, to be interpreted as excluding liquid-vapor sincevapor is relatively unsatisfactory in comparison to liquid droplets orfrozen droplets. Stated otherwise, neither of the phases is a gaseousphase.

Embodz'ment of FIGURE 2 In the embodiment of FIGURE 2, an elongatedinsulating tube or conduit 4l is associated wtih a charge-coilectingmetal sphere 42` at its upper end and wtih a metal A second insulatingconduit 48, having a diameter substantially smaller than that of conduit41, is mounted coaxially thereof and extends downwardly to the vicinityof sump element 43. Conduit 43 is connected to the lower end of smallsphere 44, being registered with a large opening in such sphere.Suitable mounting means, not shown, are provided to maintain the conduit43 fixedly in position.

A high-pressure pump 49' is provided adjacent sump element 43, having anintake 51 disposed in the body of liquid 52 in the sump. A nozzle 53 isconnected to the outlet of pump 49 and is directed axially of the smallconduit 48, so that a spray 54 of liquid droplets is passed upwardly tosphere 44. The pressure created by the pump 49 (which is onlyschematically represented) is extremely high, for example 20,0%() p.s.i.Because of the very high pressure, the droplets are ejected at enormousvelocities tending to prevent them from separating excessively due tomutual repulsion. it is to be understood, however, that the diameters ofconduits Il and 48 may be made much larger, in comparison to the lengthsthereof, than is illustrated in the drawing.

A suitable voltage source 56 is connected to the metal nozzle 53, sothat the particles emanating therefrom will be charged. T hecharge-collecting large sphere 42 is illustrated as being associatedwtih a voltage output 57. The sump element 43 is grounded at 58.

In performing the method with the embodiment of FIGURE 2, the oil,distilled water or other liquid is converted into droplet form by thenozzle 53' and is directed upwardly at high velocity into the smallsphere `d4. Since the droplets are charged by the voltage source 56, acharge builds up on the small sphere 44. This charge is transmittedthrough the conductive webs 47 to the chargecollecting sphere 42 andthus to voltage output 57.

The droplets pass through openings 46 and engage the walls of sphere 42,after which they gravitate downwardly through the annulus 61 (betweenconduits 41 and 4S) and back into the sump 43. The system is thus twophase, in the sense described relative to the previous embodiment, thatis to say between liquid in droplet form and liquid in large drops orcoherent masses.

Embodz'ment of FIGURE 3 Referring to FGURE 3, there is schematicallyillustrated an electrostatic generator which is not of the recirculatingtype, although it is to be understood that means may be employed torecirculate liquid back to the source thereof, either through theapparatus or through an outside conduit.

An insulating tube or conduit 66 is connected at its upper end to ametal sphere 67, around a large opening therein. Such sphere hasadditional openings 68 adapted to discharge droplets to the ambientatmosphere or to a suitable recirculating means. A charge-collectingrake 6% is disposed in and connected to the sphere 67, serving todeliver' charge thereto and thus to a suitable voltage output which isindicated at 71.

Mounted at the lower end of the conduit or tube 66 is a metal pressureelement or bomb 72 containing a suitahle liquid (such as an insulatingoil or distilled water) under very high pressure. A nozzle 73 is mountedat the outlet of element 72 and is directed upwardly coaxially of tube66.

A rake 74, which is connected toV a suitable voltage source 75, isdisposed in the spray 76 emanating from nozzle 73. The voltage source isalso connected to one end of the winding 77 of a potentiometer 78, theother end of the winding being connected to the metal clement 72 whichis grounded as indicated at 79. The sliding tap Sti of the potentiometer73 is electrically connected to a grid or control element 81 disposed intube d6 in the path of the spray 76. Grid or control 81 may comprise amesh of ne, electrically-conductive wires, being highly permeable to thespray 76.

aisance ln performing the method in accordance with the embodiment ofFGURE 3, the voltage source '75' is employed to impose a voltage onralre 7d and thus on the stream i6 of liquid droplets. The droplets oloil or other suitable insulating duid are ejected from nozzle '73 due tothe enormous pressure present in the pressure element or bomb 72. Thespray passes upwardly to the sphere 67 to create thereon a very highvoltage, collection of the charge being aided by the rake 69.

It is a feature of the invention that the voltage of the collectingsphere 67 may be regulated not only by varying the ilow of droplets butalso by adjusting the tap Sti of potentiometer 7&3 to give controlelement Si a desired voltage. Stated otherwise, the charge on grid 81,as determined by the position of tap or slider Si), has a bearing on thecharge delivered by the spray 76 to rake 69 and sphere 67. A veryprecise control of the voltage on sphere 67 may thus be achieved.

Additional Factors and Structure Relating t0 All Embodiments Anadditional important feature or t'ne invention is that the method ymaybe performed in a quasi or partial vacuum, in order to achieve variousadvantages including higher velocity of movement of the charge droplets,and better insulation against undesired loss of charge by the dropletsand by the domes )t6-21. To accomplish such results, a liquid (such as asuitable oil) is employed which has a low vapor pressure. The conduitit) (ElGURE l) is then evacuated, as by the means schematicallyrepresented at V. It is to be understood that evacuation means may alsobe employed with the embodiments oi FGURES 2 and 3.

When the apparatus is employed in outer space the evacuation means may,of course, be omitted. However, when the apparatus is disposed in agravitationless field it is desirable to generate artificially agravitational gradient causing the drops 36 (FIGURE l) to return to sump23.

The gravitational gradient may be created by rotating the entireapparatus around the center point C (FGURE l), for example by means of asuitable motor M and connected shaft S. Similar apparatus may beincorporated in the embodiments of FIGURES 2 and 3.

Various embodiments of the present invention, in addition to what hasbeen illustrated and described in detail, may be employed withoutdeparting from the scope of the accompanying claims.

We claim:

1. A high-voltage electrostatic generator, comprising an insulatingconduit, an insulating liquid, charge-collector means provided at oneend portion of said conduit, a series of spaced spray-collecting metalelements disposed along said conduit, nozzle means associated with therespective spray-collecting elements and directed toward saidchargecollector means, the nozzle means associated with each of saidsprayecollecting elements being adapted to transmit therefrom to theadjacent element a spray of discrete droplets of said liquid, saiddroplets being charged by the spray-collecting element associated withsuch nozzle means, memis to charge to an initial Voltage the dropletsemanating from a nozzle means remote from said chargecollector means,and pressure means to force droplet sprays at high velocities out eachof said nozzle means.

2. The invention as claimed in claim l, in which each of saidspray-collecting elements is a metal dome, and in which said pressuremeans to force sprays out said nozzle means includes an insulatingconduit having a plurality of branches communicating with the respectivenozzles.

3. The invention as claimed in claim 2, in which the major diameters orsaid domes are smaller than the internal diameter of said conduitwhereby space is pro vided between said domes and conduit forrecirculation to the inlet of said pressure means of coherent masses ofliquid.

4. The invention as claimed in claim l, in which means are provided tomaintain the space within said conduit in substantially evacuatedcondition.

5. A high-voltage electrostatic generator, which comprises an insulatingliquid, charge-coll ctor means, a substantial number ofelectrically-conductive spray-collecting elements, said spray-collectingelements being disposed in a row and in electrically-insulatedrelationship relative to said charge-collector means and to each other,the spraycoilecting element at one end o said row being relativelyadiacent said charge-collector means, nozzle means associated with eachof said spray-collecting elements and directed toward saidcharge-collector means, the nozzle means associated with each of saidspray-collecting elements other than said end element being ad( pted totransmit to the adjacent element a spray of discrete droplets of saidliquid, said droplets being charged to the voltage of thespray-collecting element associated with such nozzle means, the nozzlemeans associated with said end element being adapted to transmittherefrom to said charge-collector means a spray of discrete droplets ofsaid liquid, said droplets being charged by said end element to thevoltage thereof, means to charge to an initial voltage the dropletsemanating from a nozzle means remote from said end element, pressuremeans to force droplet sprays of said liquid at high velocities out eachof said nozzle means, and electrically-insulating means to recirculateliquid from said charge-collector means to said nozzle means.

References Cited in the le of this patent UNITED STATES PATENTS2,078,760 Hanscll Apr. 27, 1937 2,308,884 Lindenblad Ian. 19, 1943FOREIGN PATENTS 1,108,105 France Aug. 24, 1955 OTHER REFERENCESPublication: Project Satellite by Gatland, published by Wingate, London,England; pages 123, 124,

1. A HIGH-VOLTAGE ELECTROSTATIC GENERATOR, COMPRISING AN INSULATING CONDUIT, AN INSULATING LIQUID, CHARGE-COLLECTOR MEANS PROVIDED AT ONE END PORTION OF SAID CONDUIT, A SERIES OF SPACED SPRAY-COLLECTING METAL ELEMENTS DISPOSED ALONG SAID CONDUIT, NOZZLE MEANS ASSOCIATED WITH THE RESPECTIVE SPRAY-COLLECTING ELEMENTS AND DIRECTED TOWARD SAID CHARGECOLLECTOR MEANS, THE NOZZLE MEANS ASSOCIATED WITH EACH OF SAID SPRAY-COLLECTING ELEMENTS BEING ADAPTED TO TRANSMIT THEREFROM TO THE ADJACENT ELEMENT A SPRAY OF DISCRETE DROPLETS OF SAID LIQUID, SAID DROPLETS BEING CHARGED BY 